Amperometric affinity assay and electrically stimulated complexes of nucleic acids

A method for determining an affinity of a first nucleobase-containing sequence for a second nucleobase-containing sequence includes providing a test medium containing the first nucleobase-containing sequence and the second nucleobase-containing sequence, applying a voltage across the test medium, measuring a test electric current through the test medium; and determining the affinity by evaluating whether the test electric current is equivalent to a reference electric current of a reference medium containing a longer of the first nucleobase-containing sequence and the second nucleobase-containing sequence. A complex in an electrically-stimulated phase contains at least two nucleobase-containing sequences in a medium, wherein the electrical conductivity of the medium increases linearly without a plateau as the temperature of the medium approaches and exceeds a Tm of the complex.